1. Field of the Invention
The present invention relates to a method of cutting and separating a bent board into individual small divisions, and more particularly to an improvement in such cutting-and-separating method in reducing inaccurate separation which is caused by the bend of the board.
2. Related Arts
Referring to FIG. 9, a semiconductor wafer 30 is sucked and held on a chuck table 31, and the semiconductor wafer 30 can be diced into individual chips when a rotary blade 32 traverses the chuck table 31 in the X-axis direction.
Likewise, a chip size packages board (abbreviated as CSP board) 33 (see FIG. 10) can be cut and separated into individual pellets, i.e. CSPs, when the rotary blade 32 traverses the board along each cutting line 34 (broken line).
Such a CSP board 33 has a plurality of semiconductor chips arranged crosswise on a board material and hermetically attached thereto by resin such as glass epoxy resin (not shown the details), thus providing an integrated form as shown in FIG. 10. As seen from FIGS. 11 and 12, the board 33 has a significant bend. It was caused when the resin is exposed to a raised temperature at which the sealant is applied to a crosswise arrangement of chips, and when the sealant is set to provide a hermetically sealed object. Such a bent CSP board, when put on the chuck table 31 cannot be sucked thereon, thus preventing it from being fixedly held thereon. For this reason no smooth cutting is permitted.
Smooth and correct cutting cannot be permitted unless the board is held on the chuck board in stable condition.